Rinse thawed okra briefly in a colander. Let drain thoroughly. Transfer okra to a large mixing bowl.
In a separate bowl, whisk together buttermilk and egg whites until combined.
In another bowl, combine yellow cornmeal, all-purpose flour, sea salt, black pepper and garlic powder. Whisk until evenly blended.
Working in small batches, lightly coat okra pieces in the buttermilk mixture.
Allow excess buttermilk to drip off by giving a gentle shake in your open hand, and immediately toss in the dry cornmeal mixture until fully and evenly coated.
Place the battered okra onto a clean plate.
Pour enough vegetable oil into a heavy-bottomed skillet or deep-fryer to submerge the okra pieces.
Place over medium-high heat and heat until it reaches 375°F (190°C).
Carefully add a single layer of battered okra to the hot oil, making sure not to overcrowd the pan. Fry for 3 to 5 minutes or until each piece turns a deep, golden brown and crispy.
Use a slotted spoon to transfer the fried okra to a paper towel-lined plate to drain excess oil.
Repeat until all okra is fried.
Arrange the hot, crispy fried okra on a serving dish. Enjoy as a standalone snack or as a side to your favorite Southern meal. For optimum crunch and an authentic taste, serve these golden morsels fresh from the fryer alongside a tangy dipping sauce like remoulade or spicy ketchup.